This study explores the development and influence of visual media on social movement activism in Slovenia in the 1980s and in the new millennium. Because of the changes in the political context during these decades, we aimed to determine whether there were differences between the political posters displayed by selected Slovenian social movements during the 1980s and those in the new millennium. Acknowledging the shift in the type of regime, as well as the transition to democracy, we observed major milestones in the poster campaigns of social movements and the forces that influenced them. We identified four modes of protest in these poster campaigns among which the avant-gardist rationale in the 1980s significantly influenced those in the new millennium. In addition to that, we found that the introduction of the principles of political marketing and political pluralism influenced the protest poster campaigns when the hiring of campaign professionals became affordable. Our findings indicate that contemporary modes of poster campaigns rely on financial and organisational resources, and they are characterized by the search for an ideological enemy of the state. Our findings are based on a content analysis of 116 protest posters that were collected using a purposive sampling of critical cases. The findings of this study offer original insights into the poster campaigns of social movements in the context of the transition from propaganda to political communication in a democratic society. The form of visual analysis applied in the study is original because it is conventionally employed in textual, and not visual analysis.